Looking at this again ... the PFC might be really better for the efficiency and those 10W-20W wasted in the PFC will be compensated by not having the performance drop caused otherwise.

PFC will need 504 chips (next step 9 panels) and lower (~240kHz) max SPI, but as it turns out it should still be enough for proper communication.

I will be few chips short for 9 panels and there will be no chips left for replacements after the fireworks, but will definitely try the PFC setup if enough chips survive the first tests